What causes water retention?

Marjorie Nolan Cohn
Nutrition & Dietetics
Water retention is also called edema; it's the buildup of excess fluid in the body. Edema is most commonly seen in the feet and ankles. Because of gravity, swelling is particularly noticeable in these locations.

But swelling due to water retention involves the enlargement of organs, skin, or other body structures. It is caused by excessive buildup of fluid in the tissues. This build up can lead to a rapid increase in weight over a short period of time (days to weeks). Swelling can occur throughout the body (generalized) or it may be limited to a specific part of the body (localized).

Certain medications may also cause water retention:
  • Hormones, like estrogen (in birth control pills or hormone replacement therapy) and testosterone
  • A group of blood pressure lowering drugs
  • Steroids
  • Antidepressants
Water retention has many possible causes:
  • Venous insufficiency, a common problem caused by weakened valves in the veins of the legs. This makes it more difficult for the veins to pump blood back to the heart, and leads to varicose veins and buildup of fluid.
  • Severe chronic lung diseases, including emphysema and chronic bronchitis, increase pressure in the blood vessels that lead from the heart to the lungs. This pressure backs up in the heart. The higher pressure causes swelling in the legs and feet.
  • Congestive heart failure, a condition in which the heart can no longer pump efficiently, causes fluid buildup in the lungs and other parts of the body. Swelling is often most visible in the feet and ankles.
  • Low protein levels in the blood caused by malnutrition, kidney and liver disease can cause edema. The proteins help to hold salt and water inside the blood vessels so fluid does not leak out into the tissues. If the most abundant blood protein, called albumin, gets too low, fluid is retained and edema occurs, especially in the feet, ankles and lower legs.
Lots of different things cause water retention. There are many causes of retaining extra water that can involve different organs of the body. For example, the kidneys work to clean the blood and dispose of bodily wastes. When the kidneys don’t work properly, they cannot filter properly and they retain extra sodium and water that should have been urinated out. Sometimes water retention can be found in a specific area of the body. Some people have poor blood flow and it is hard to get the blood back up to the heart. Due to gravity, this blood can collect in the legs and cause fluid to move into the tissues causing the legs to swell. Allergic reactions from bee stings or bug bites can cause fluid accumulation at the site of the sting or bite.
Water retention can be caused by increased sodium levels in your diet or through a change in the menstrual cycles. The most common myth of water retention is that a lot of people think drinking too much water will make them bloated and become heavier but the opposite is true. The more water you drink, the more water and waste products your body will flush out. This will help your body get rid of harmful toxins, making you feel less bloated and lose more water weight over time.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.